The invention relates to internal combustion engine testing apparatus, and more particularly relates to apparatus for enabling the (1) acquisition of engine condition data, (2) analysis of the condition data to obtain diagnostic data, and (3) display of the diagnostic data.
In U.S. Application Ser. No. 641,362, now abandoned entitled "ENGINE TEST AND DISPLAY APPARATUS", filed Dec. 16, 1975, in the names of Cashel et al., a system for performing engine analysis and for displaying the results thereof on a CRT screen is described. In such a system, which recovers raw measurements from an internal combustion engine, it is necessary to process the measurements to a form which communicates to the operator the operating conditions of the engine. In order to provide a correct operational analysis of the particular vehicle engine being tested, the processed measurements must be compared with a data base containing the normal operating conditions of the engine.
The system described in the above-identified application provides a means for monitoring an internal combustion engine and making necessary measurements with regard to the engine's operation. It further provides a means for processing these measurements, and visually displaying the measurement results to the operator.
However, the operator must provide his own data base (as, for example, through engine operational manuals and look-up tables) related to the specific engine under test. The operator must use his own ingenuity and experience to analyze the discrepancies found between the information of the tables and the empirical measurements taken.
Such an analysis is limited by the mechanic's skill and experience. The mechanic is also required to maintain voluminous look-up tables and manuals, and is forced to continually purchase new manuals and update existing ones.
However, if the operator mechanic had a large scale computer system in his garage, he could quickly call for operational table data to be displayed on the computer readout to make his comparisons. The operator might also feed into the computer the raw measurement data and program the computer to analyze the discrepancies existing between the empirical measurements and the data base.
The average engine mechanic, however, does not have the computer skills nor the programming skills to successfully operate such a system. Nor does the mechanic have the time to continually update the data base as new automobiles come onto the market throughout the year. And, finally, the great expense of a large scale computer system makes such an idea totally impractical.